Philippa Kaur

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    in Humans

    Last meal of a man mummified in a bog reconstructed after 2400 years

    By Christa Lesté-Lasserre

    The well-preserved head of Tollund Man A. Mikkelsen
    An ancient man ate a simple meal of cooked cereals and fish before being hanged and dumped in a bog 2400 years ago.
    Tollund Man was roughly 40 years old when he died in what is now Denmark. He was probably offered as a human sacrifice, and the peat bog he was buried in mummified his body in extraordinary detail. Dozens of other Iron Age Europeans were sacrificed in the same way, and they are collectively referred to as “bog bodies”.
    Danish scientists first analysed Tollund Man’s intestinal contents shortly after his body was discovered in 1950. They found 20 plant species and one species of parasite.Advertisement
    But now Nina Helt Nielsen at Museum Silkeborg in Denmark and her colleagues have run new analyses on the contents of Tollund Man’s large intestine, investigating plant fossils, pollen and – for the first time in any bog body – a full range of non-pollen microfossils, steroids and proteins.
    Ingredients that made up Tollund Man’s last mealN.H. Nielsen
    The research revealed the presence of intestinal worm proteins and eggs – belonging to whipworm (Trichuris), tapeworm (Taenia) and mawworm (Ascaris) – as well as the man’s partially digested dinner. He ate porridge made up of around 85 per cent barley, 5 per cent flax and 9 per cent seeds from a plant called pale persicaria. Food crust indicated that the porridge was slightly burned and had been cooked in a clay pot.

    About 20 other species represented less than 1 per cent of the whole meal and were probably consumed accidentally. Tollund Man had also eaten a fatty-boned fish, like eel. He probably picked up the parasites from eating poorly cooked meat and drinking unclean water well before his death, says Nielsen.
    As for his last meal, it was mostly ordinary for the time. “I’m pretty sure we would see something similar if we analysed the gut contents of other bog bodies,” says Nielsen – although the pale persicaria seeds might have been a special addition as part of a sacrificial ritual.
    At about 1350 kilocalories, Tollund Man’s last meal would have provided half his daily nutritional needs – and has been preserved in such detail that “we could almost reproduce the recipe”, she says.
    Journal reference: Antiquity, DOI: 10.15184/aqy.2021.98

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    in Humans

    Puzzle-solving great apes: The shared abilities underpinning language

    A project testing great apes’ puzzle-solving abilities could offer insight into the mental abilities underpinning language. Solving the puzzles involves the same sorts of mental abilities humans use in speech, so by studying the gorillas, Birkbeck researchers hope to learn more about language development in another great ape: us. New Scientist has been following this pioneering research, discovering that humans are not as unique as we’d like to think.

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    in Humans

    Meet the puzzle-solving gorillas shedding light on how speech evolved

    By Clare Wilson

    [embedded content]
    There are many ways that our great ape relatives can remind us of ourselves: through their anatomy, cleverness and social relationships, for instance. But never has the resemblance been so striking for me as today, when I watch gorillas carrying out a very human past-time: solving puzzles.
    The gorillas in question live at Port Lympne Reserve in Kent in the UK. The task involves moving a hazelnut treat down a vertical maze using sticks or the inbuilt cogs, until it is released at the bottom. It is very similar to a game I loved as a child, called Downfall, … More

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    in Space & Astronomy

    The latest picture of a black hole captures Centaurus A’s massive jets

    The Event Horizon Telescope is expanding its portfolio of black hole images.

    In 2019, the telescope unveiled the first image of a black hole, revealing the supermassive beast 55 light-years from Earth at the center of galaxy M87 (SN: 4/10/19). That lopsided orange ring showed the shadow of the black hole on its glowing accretion disk of infalling material. Since then, observations from the Event Horizon Telescope, or EHT, have yielded more detailed views of M87’s black hole (SN: 9/23/20). Now, EHT data have revealed new details of the supermassive black hole at the heart of a galaxy near our own, called Centaurus A.

    Rather than zooming in close enough to see the black hole’s shadow, the new picture offers the clearest view yet of the powerful plasma jets erupting from the black hole. This perspective gives insight into how supermassive black holes blast such plasma jets into space, researchers report online July 19 in Nature Astronomy.

    “It’s a fairly impressive feat,” says radio astronomer Craig Walker of capturing the new high-resolution image. “These [jets] are some of the most powerful things in the universe,” says Walker, of the National Radio Astronomy Observatory in Socorro, N.M., who was not involved in the work. Because such superfast plasma streams are thought to influence how galaxies grow and evolve, astronomers are keen to understand how the jets form (SN: 3/29/19).

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    Researchers pointed the global network of radio dishes that make up the EHT at Centaurus A for six hours in April 2017, during the same observing run that delivered the first picture of a black hole (SN: 4/10/19). About 12 million light-years from Earth, Centaurus A is one of the brightest galaxies in the sky and is known for the huge jets expelled by its central black hole.

    “They extend to pretty much the entire scale of the galaxy,” says Michael Janssen, a radio astronomer at the Max Planck Institute for Radio Astronomy in Bonn, Germany. “If we were to see radio light [with our eyes], and we were to look at the night sky, then we would see these jets of Centaurus A as a structure that is 16 times bigger than the full moon.”

    Using the EHT, Janssen and colleagues homed in on the base of those jets, which gush out from either side of the black hole’s accretion disk. The new image is 16 times as sharp as previous observations of the jets, probing details less than one light-day across — about four times the distance from the sun to Pluto. One of the most striking features that the image reveals is that only the outer edges of the jets seem to glow.

    The supermassive black hole in the galaxy Centaurus A launches two jets of plasma in opposite directions (zoomed-out view of the jets at left). In a new close-up view taken by the Event Horizon Telescope (at right; estimated location of the black hole indicated with an arrow), the jet moving toward Earth points toward the image’s top left, with two bright edges and a dark center. The jet moving away from Earth, also bright only at the edges, points toward the bottom right.M. Janssen et al/Nature Astronomy 2021

    “That’s still a puzzle,” Janssen says. One possibility is that the jets are rotating, which might cause material in some regions of the jets to emit light toward Earth, while others don’t. Or the jets could be hollow, Janssen says.

    Recent observations of a few other galaxies have hinted that the jets of supermassive black holes are brighter around the edges, says Denise Gabuzda, an astrophysicist at University College Cork in Ireland, who wasn’t involved in the work. “But it’s been hard to know whether it was a common feature, or whether it was something quirky about the few that had been observed.”

    The new view of Centaurus A’s black hole provides evidence that this edge-brightening is common, Gabuzda says. “It’s fairly rare to be able to detect the jets coming out in both directions, but in the images of Centaurus A … you can clearly see that both of them are brighter at the edges.”

    The next step will be to compare the EHT image of Centaurus A with computer simulations based on Einstein’s general theory of relativity, to test how well relativity holds up in this extreme environment, Janssen says. Examining the polarization, or orientation, of the light waves emanating from Centaurus A’s jets could also reveal the structure of their magnetic fields — just as polarization revealed the magnetism around M87’s black hole (SN: 3/24/21). More

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    in Humans

    Just 1.5 to 7 per cent of the modern human genome is uniquely ours

    By Krista Charles

    A very small part of our genome might be unique to modern humansCueImages/Alamy
    Modern humans have been around for about 350,000 years. In that time, we have continued to evolve and our DNA has changed – but, only a small per centage of our genome may be unique to us.
    Nathan Schaefer at the University of California, San Francisco, and his colleagues created a tool called the Speedy Ancestral Recombination Graph Estimator (SARGE), which allowed them to estimate the ancestry of individuals.
    More specifically, it helped identify which bits of the modern human genome aren’t shared with other hominins – meaning they weren’t present in the ancient ancestors we shared with Neanderthals and Denisovans, and also haven’t been introduced to the human gene pool through interbreeding with these ancient humans.Advertisement
    “Instead of building a tree across the genome that shows how a bunch of genomes are related on average genome-wide, we wanted to know what the ancestry of individuals looks like at specific sites in the genome,” says Schaefer. “We basically wanted to be able to show how everyone is related at every single variable position in the genome.”
    The team analysed one Denisovan, two Neanderthal, and 279 modern human genomes to distinguish what parts of the genome separate modern humans from archaic hominins. They found that only 1.5 to 7 per cent of the modern human genome is unique to us.

    The figure may seem low but that is partly because we inherited plenty of DNA from the ancient ancestral species that ultimately gave rise to modern humans and the Neanderthals and Denisovans.
    What’s more, modern humans then interbred with Neanderthals and Denisovans, picking up even more DNA that isn’t unique to our lineage.
    “It’s true that individual humans have a very low per cent of their genome that might have been from Neanderthal or Denisovan ancestry – non-Africans can have between 1.5 to 2.1 per cent of their genome that originated from Neanderthal ancestry,” says Schaefer.
    But we know that the exact form taken by that small amount of Neanderthal DNA varies from individual to individual – meaning two people can both have 2 per cent Neanderthal DNA but share little Neanderthal DNA in common. These differences add up, says Shaefer. Some estimates suggest about 40 per cent of the Neanderthal genome can be pieced together by combining genetic information from a wide variety of living people.
    The mutations that contribute to uniquely human features are contained within a small part of the genome and seem to mainly affect genes related to brain development.
    “Knowing how those variants affect human mental capacities would help us understand the cognitive differences between humans and Neanderthals,” says Montgomery Slatkin at the University of California, Berkeley.
    Journal reference: Science Advances, DOI: 10.1126/sciadv.abc0776
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    in Humans

    Chris Mason interview: Let's tweak human DNA for life on other planets

    To become an interplanetary species, we may have to genetically engineer ourselves to be more resilient, says geneticist Chris Mason. He has a 500-year plan for life away from Earth

    Earth

    14 July 2021

    By Joshua Howgego

    Rocio Montoya
    CHRIS MASON likes to think about the future. He isn’t dreaming about a summer holiday, or even planning his retirement. His thoughts extend much further – to the point where Earth is no longer a suitable home for humans.
    Alarmed at the prospect, Mason has sketched out a plan of action in the form of his book The Next 500 Years: Engineering life to reach new worlds. It covers some of the usual ground: how we will first establish bases on the moon and Mars, and later on the solar system’s outer moons. Eventually, we will make an epic trip … More

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    in Humans

    How medical tests have built-in discrimination against Black people

    By Layal Liverpool

    Race-based adjustments are widely used in some diagnostic testsSean Justice/Getty Images
    THE assumption that Black people have a lower level of cognitive function than white people was, until recently, built into a formula used by the US National Football League to settle head injury lawsuits. The NFL has now pledged to stop using this “race-norming” formula, but race-based adjustments in routine diagnostic tests remain pervasive in mainstream medicine. Although some scientific organisations are working to remove such adjustments, many contacted by New Scientist declined to take a stance on the issue, which … More

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    in Humans

    The lowdown on stretching: How flexible do you actually need to be?

    Many people strive to touch their toes or do the splits, but it is perfectly possible to get all the benefits of stretching without pushing your body to its limits

    Health

    14 July 2021

    By Caroline Williams

    Harriet Noble/Studio Pi
    “I BEND so I don’t break.” No one knows who first coined this phrase, but search for it online and you will find it accompanying numerous pictures of yogis in various states of contortion. Flexibility, according to common wisdom, is not only impressive to look at, but something we should actively work towards.
    Scientifically, however, the question of whether we should stretch to become more flexible has been difficult to answer. Assumptions about the benefits of stretching to prevent sports injuries and greater flexibility being better for our overall physical fitness hadn’t been confirmed by studies. Does it matter if you can’t touch your toes, let alone do the splits? Even in sports science, where most of the research has been conducted, there has been little agreement.
    In recent years, though, answers have started to emerge. The surprising outcome is that, while stretching may well be good for us, it is for reasons that have nothing to do with being able to get your leg behind your head.
    One thing is for sure: stretching feels good, particularly after a long spell of being still. We aren’t the only species to have worked this out. As anyone with a dog or cat will know, many animals take a deep stretch after lying around. This kind of stretching, called pandiculation, is so common in nature that some have suggested it evolved as a reflex to wake up the muscles after a spell of stillness.
    Pandiculation aside, other species don’t seem to spend any time maintaining and extending their range of motion. Which raises the question, is there any reason why we should? … More